Exoplanet detection surveys over the last twenty years have revealed a surprising diversity of planets orbiting other stars— this revolution is fueled by fundamental questions about the place of the Earth and the Solar System in the Universe. How do planets form? What range in architectures of planetary systems exist? How does our Solar System fit into this context?
The study of exoplanet atmospheres is the next step in leveraging exoplanetary detections. This is because a planet’s atmosphere provides a fossil record of its primordial origins and controls its fate, size, appearance, and ultimately its habitability. In this context, I present comparative exoplanetology programs that aim at characterising planetary systems transiting nearby stars through the observations of their atmospheres. Our findings on the atmospheric composition and physical properties provide insights into the formation and evolution of planetary systems and enhance our understanding of our own Solar System’s formation. Finally, I also present strategies for probing habitable exoplanet atmospheres in the quest for bio-signatures.